1 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Moisture Assessment WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010

2 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov By attending this session, participants will gain an understanding of: Symptoms of moisture problems in houses. Moisture sources. Moisture terms and concepts. How to measure relative humidity (RH). How to use a psychrometric chart. Moisture control strategies. Moisture assessment tools. Learning Objectives MOISTURE ASSESSMENT

3 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms #1 Excessive window condensation Photo courtesy of PA WTC MOISTURE ASSESSMENT

4 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms #2 Frost on underside of roof sheathing MOISTURE ASSESSMENT Photo courtesy of PA WTC

5 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms #3 Mold on interior surfaces Photo source: PA WTC Photo MOISTURE ASSESSMENT Photo courtesy of PA WTC

6 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms #4 Peeling Exterior Paint MOISTURE ASSESSMENT Photo courtesy of PA WTC

7 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Standing Water in Basements MOISTURE ASSESSMENT Photo courtesy of PA WTC Symptom #5

8 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Foundations. Unvented space heaters. Unvented dryers. Disconnected ventilation fans. Drying wood indoors. Excessive mechanical or passive humidification. Moisture Sources These water stains are a result of fan venting into the attic. MOISTURE ASSESSMENT Photo courtesy of PA WTC

9 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Sources of Water Vapor MOISTURE ASSESSMENT

10 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Condensation: water vapor transformed to liquid water. Evaporation: liquid water transformed to water vapor. Absolute Humidity (vapor pressure): the ratio of water vapor to a given volume of air. Relative Humidity (RH): the ratio of the amount of moisture in the air compared to amount of moisture that the air can hold. Dew Point: the temperature at which condensation occurs. Important Terms and Concepts MOISTURE ASSESSMENT

11 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Measuring Relative Humidity Sling Psychrometers Two thermometers side by side. One is wrapped in wet wick (wet bulb), the other is dry (dry bulb). Spinning it around speeds temperature stabilization. Plot wet bulb and dry bulb temperature on psychrometric chart to determine dew point and RH. Bacharach Sling Psychrometer psychrometer.htm MOISTURE ASSESSMENT

12 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Dry bulb = 80° Wet bulb = 66° Dew point = 60° RH = 50% Dry bulb = 80° Wet bulb = 66° Dew point = 60° RH = 50% Grains of water per pound of dry air MOISTURE ASSESSMENT Psychrometric Chart #1

13 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov 156 Psychrometric Chart #2 78 Grains of water per pound of dry air MOISTURE ASSESSMENT

14 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Grains of water per pound of dry air MOISTURE ASSESSMENT Psychrometric Chart #3

15 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Grains of water per pound of dry air MOISTURE ASSESSMENT Psychrometric Chart #4

16 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Grains of water per pound of dry air MOISTURE ASSESSMENT Psychrometric Chart #5

17 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Warm, wet air contacting cold surfaces creates condensation instantly. Cold winter air typically contains very little moisture and therefore has a low RH. When that air is heated, the RH drops even lower. RH below 15% can lead to respiratory problems, failure of furniture glue and other problems. RH: Things to Remember MOISTURE ASSESSMENT

18 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Attic Case Study #1 Floored Attic and First Condensing Surface MOISTURE ASSESSMENT Photo courtesy of PA WTC

19 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms –Condensation or mold growth on attic surfaces (rafters, sheathing or underside of flooring). Possible Reasons –Moderate to high interior moisture source. –Attic surface temps are below the dew point of the indoor air. –Air leaks to attic. Control Strategies –Source control. –Air seal the attic. Attic Case Study #2 MOISTURE ASSESSMENT

20 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Basement Case Study #1 Mold on cool interior corner. Symptom Condensation evident on basement walls. Reason Light to moderate interior moisture source. Basement walls are below the dew point of the indoor air. MOISTURE ASSESSMENT Photo courtesy of PA WTC

21 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Control moisture sources. Remove susceptible materials. Educate occupants to: –Mechanically dehumidify. – Increase air flow in basement (fans). – Close basement openings during hot humid periods. Basement Case Study #2 MOISTURE ASSESSMENT

22 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Symptoms Wet wood. Condensation on foundation surfaces. Possible Reasons High ground moisture source. Warm humid air entering vents from outside. Crawl space surfaces are below the dew point of the outside air. Crawl Space Case Study #1 Water droplets of condensation on AC ducts. MOISTURE ASSESSMENT Photo courtesy of PA WTC

23 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Install a ground vapor retarder. Control moisture sources and remove susceptible materials. Consider converting to a conditioned crawl space. Crawl Space Case Study #2 Conditioned crawlspace with air sealed and insulated walls. MOISTURE ASSESSMENT Photo courtesy of INCAP

24 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov Clear understanding of moisture management principles. Senses - Visual inspection –Evidence of condensation. –Evidence of mold. Communication Skills –Know what questions to ask. –Documentation is vital. Wood Moisture Meter –To make quantitative assessments on wood moisture content. Psychrometer –To determine real time RH levels. Digital Camera Tools of the Trade MOISTURE ASSESSMENT

25 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov PhotoSource: PA WTC MOISTURE ASSESSMENT Moisture Meters Photos courtesy of PA WTC

26 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010eere.energy.gov The first step in doing a moisture assessment is to look for visible signs of moisture and moisture sources in the house. Plotting the wet bulb and dry bulb temperatures on a psychrometric chart gives dew point and relative humidity. Understanding the effects of temperature and vapor pressure on RH can help identify solutions. Source control, air sealing, ventilation, and thermal improvements are important moisture mitigation strategies. Photos and diagnostic equipment help document existing conditions. Summary MOISTURE ASSESSMENT